Track down FreeBSD concurrent test failures

[derekparker]

There are a few tests on the FreeBSD port (namely the concurrent or any parallel_next test) which are currently skipped and must be investigated as to why they are failing.

Some of the failing tests may be related to https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=236035.

[derekparker]

cc @rayrapetyan

[derekparker]

Here is a list of skipped tests.

$ go test ./... -v | grep -A1 SKIP
--- SKIP: TestNextConcurrent (0.00s)
    proc_test.go:528: test is not valid on FreeBSD
--
--- SKIP: TestNextConcurrentVariant2 (0.00s)
    proc_test.go:567: test is not valid on FreeBSD
--
--- SKIP: TestBreakpointCounts (0.00s)
    proc_test.go:1407: test is not valid on FreeBSD
--
--- SKIP: TestCondBreakpoint (0.00s)
    proc_test.go:1627: test is not valid on FreeBSD
--
--- SKIP: TestCondBreakpointError (0.00s)
    proc_test.go:1654: test is not valid on FreeBSD
--
--- SKIP: TestNextParked (0.00s)
    proc_test.go:1973: test is not valid on FreeBSD
--
--- SKIP: TestStepParked (0.00s)
    proc_test.go:2027: test is not valid on FreeBSD
--
--- SKIP: TestStepConcurrentDirect (0.00s)
    proc_test.go:2351: test is not valid on FreeBSD
--
--- SKIP: TestStepConcurrentPtr (0.00s)
    proc_test.go:2420: test is not valid on FreeBSD
--
--- SKIP: TestCallConcurrent (0.00s)
    proc_test.go:4386: test is not valid on FreeBSD
--
--- SKIP: TestOnPrefix (0.00s)
    command_test.go:428: test is not valid on FreeBSD
--
--- SKIP: TestOnPrefixLocals (0.00s)
    command_test.go:484: test is not valid on FreeBSD
--
--- SKIP: TestIssue387 (0.00s)
    command_test.go:542: test is not valid on FreeBSD
--
--- SKIP: Test1ClientServer_CondBreakpoint (0.00s)
    integration1_test.go:976: test is not valid on FreeBSD
--
--- SKIP: TestClientServer_CondBreakpoint (0.00s)
    integration2_test.go:1059: test is not valid on FreeBSD